1. Field of the Invention
This invention relates to an apparatus such as a camera applicable to film cartridges of various kinds.
2. Description of Related Art
A camera disclosed in Japanese Laid-Open Patent Application No. SHO 55-22799 is arranged to use a film cartridge having information about the film recorded as magnetic information on a disk which moves integrally with the film in association with transportation of the film and to read the information when the film is supplied to the camera. Meanwhile, Japanese Laid-Open Utility Model Application No. SHO 58-183695 discloses a cassette tape arranged to record information about the cassette tape in a bar code on a tape take-up reel of the cassette tape. It is possible to have the above-stated film information recorded also in a bar code on the disk in the same manner. The film information then can be automatically set by arranging the camera to read the film information by optical means such as a photo-reflector or the like at the commencement of film transportation.
Further, Japanese Laid-Open Patent Application No. HEI 2-114248 discloses a film cartridge arranged to indicate whether the film contained therein has not been used, i.e., has been unexposed, or has been used, i.e., has been exposed, by an indication means which rotates along with the rotation of a supply spool disposed within the film cartridge. A camera adopted for this film cartridge is arranged to detect the indication made by the indication means, so that a double exposure is avoidable even where the camera is loaded with a photographed (used) film, i.e., an exposed film. In order to let such double exposure preventing means effectively function, the camera must be arranged to set the indication means in such a position to show the completely used (exposed) state of the film after completion of photographing on all frames of the film. The cameras arranged in this manner are disclosed, for example, in Japanese laid-open patent applications No. HEI 4-301829 and No. HEI 4-366933, etc.
There have been developed various methods for automation of camera operations, including an automatic film loading operation which simplifies the conventional film loading. Unlike the conventional manner in which the camera operator is required to manually set a leader part of film in a predetermined position by pulling it out from the film cartridge, the leader part of the film is arranged to be automatically pulled into the camera by means of a motor or the like when the film cartridge is simply set in a predetermined position within the camera.
In showing the automatic film loading function of a camera to a likely buyer by demonstrating it at a camera store (or shop), the camera must be actually loaded with a film cartridge. However, use of a film cartridge containing an unexposed film therein for a demonstration would cause a useless shot or shots to ruin the film in part after loading. Besides, when the useless shots are taken to the last frame portion of the film, the film is automatically rewound. In such a case, the film cartridge would come to inhibit further photographing. Such a demonstration is uneconomical.
To solve this problem, a camera disclosed in Japanese Laid-Open Utility Model Application No. SHO 60-172141 is arranged to have a demonstration mode for showing the functions and the method for operating the camera. The camera disclosed in this utility model application necessitates an operation on a switch in selecting the demonstration mode. However, the switching operation tends to be erroneously performed by the operator and is, therefore, not desirable.
It has been also developed to arrange an empty film cartridge having no film therein to be used for demonstrations at a camera store. Hereinafter, such a film cartridge will be called a demonstration film cartridge. The demonstration film cartridge is arranged to be distinguishable from a normal film cartridge by means of the bar code information mentioned above.
It has been practiced to arrange a camera to position the film, with a film cartridge placed within the camera, by detecting perforations provided in the film in carrying out various actions such as an automatic loading action by automatically moving the film to a photographable position, a one-frame winding action after a shutter release action, a film rewinding action and. When there is no film cartridge within the camera, an abnormal camera action is prevented, for example, by not performing any film transporting action with the absence of a film cartridge detected or by inhibiting the film perforation detecting action. However, in the case of the above-stated demonstration film cartridge, no film is contained in the film cartridge when the camera is loaded with the film cartridge. It is impossible for the camera to immediately detect the absence of film. As a result, the camera makes an autodiagnosis to decide that the camera is out of order as no perforation is detectable during the process of its film transporting action.
Further, the above-stated arrangement for indicating the exposure state of the film comes to show an "exposed" state after completion of photographing for all the frames of the film and to prevent any double exposure even if the same film is loaded on a camera again. However, the double exposure inhibiting arrangement is inconvenient in the case of the demonstration film cartridge, because the demonstration film cartridge is to be repeatedly used at a store. Bringing the setting of "exposed" state back to the initial setting of "unexposed" state necessitates use of a special tool, which prevents ordinary camera operators from easily changing the set state of a film. However, it is not easy to have such a special tool ready for use at every camera store.
An arrangement for rendering such a photographed (exposed) film usable by setting some mode in the process of manufacture at a factory or the like is disclosed in Japanese Laid-Open Patent Application No. HEI 7-295067. According to that disclosure, the contents of a nonvolatile storage element such as an EEPROM or the like are rewritten to bring forth a predetermined mode. However, it is difficult to set such a mode at a camera store.
The indication of the exposure state of film mentioned above is arranged in general to be set upon completion of film rewinding as the indicating part rotates along with the film supply spool. In the case of the demonstration film cartridge, however, the film cartridge can be taken out to the outside without film rewinding, because the film cartridge contains no film. Therefore, the exposure state indication tends to be not set as expected, because of no film rewinding action.
Another problem with the prior art arrangement lies in that, if film sensitivity is set at a low (ISO) value at the time of demonstration at a camera store, the flash device of the camera tends to flash, thereby increasing the electric energy consumption of a battery of the camera.
A further problem of the prior art arrangement lies in that, once a camera is loaded with a film cartridge, it is difficult to make a discrimination between an ordinary film cartridge and the demonstration film cartridge.